The present invention is directed to an x-ray diagnostics installation having a storage luminescent screen for the latent storage of the respective x-ray image. The installation comprises an x-ray generator having an x-ray exposure means connected to the generator for projecting an x-ray beam through a patient to create an x-ray image, a read-out means wherein the storage luminescent screen is caused to luminesce pixel-by-pixel by a surface-shaped scanning with a scan beam of a radiation source, a detecting means for acquiring the light emitted by the storage luminescent screen and an image reproduction system for creating an image from the light received by the detector means.
X-ray diagnostics installations of this type are disclosed in U.S. Pat. No. 4,710,626, whose disclosure is incorporated herein by reference thereto and which claims priority from the same Japanese Application as European Published Application A-0 094 843. In this type of x-ray diagnostics installation, the storage luminescent screen is radiated with x-rays in a registration station so that hole electrons, that are stored in a potential trap, are produced therein. Subsequently, the exposed storage luminescent screen is conveyed into a read-out station in which the read-out means scans the entire surface of this storage luminescent screen pixel-by-pixel with an additional radiation source, for example, a laser, so that the electrons stored in the traps are excited and can fall back into recombination centers whereby an energy difference is beamed out in the form of light quanta having a wavelength that is different in comparison to the wavelength of the radiation source. This image is then supplied in a known fashion to an image reproduction system that effects an image reproduction either on a monitor or as a hard copy.
For surface-wise scanning of the storage luminescent screen, the laser beam is deflected, for example, in a horizontal direction by a mirror and is displaced in a vertical direction, so that all the picture elements lying on the storage luminescent screen are successively scanned. The light emitted by the storage luminescent screen is then acquired by an opto-collector and is imaged on a light-sensitive entry face of the detector. An output signal of the detector is supplied, for example, to a normal video chain for reproduction of the x-ray image on a monitor. U.S. Pat. No. 4,587,036, whose disclosure is incorporated herein by reference thereto and which claims priority from German Application 33 47 207, discloses europium-activated barium fluorobromium chloride compounds which can be excited with visible light (photo-stimulation) and can thereby be employed as stimulatable phosphors. Normally employed He-Ne lasers that produce focussed beams having a wavelength of 633nm can be employed for exciting this stimulatable phosphor.
Such x-ray diagnostics installations, however, have a disadvantage. For example, due to the accommodation of the storage films in light-tight cassettes, which is due to the removal of the foil in the read-out machine with all mechanical manipulations and due to the preliminary read-out of the film for acquiring dynamics, extremely long time spans will occur until the presence of the x-ray image on a video monitor or, respectively, on the hard copy master will be obtained.